The gross-out quotient on this one is pretty high, but it’s an interesting question.
Let’s say you are Aron Ralston, the guy who got stuck in the Utah wilderness and had to saw his own arm off because he got it stuck under a rock. There you are, stuck alone somewhere (a desert, an island, in a refrigerated boxcar) and no one knows where you are. Did you know that the most likely way for you to die is dehydration? OK, that’s unless you’re in the refrigerated boxcar in which case death will most likely come by hypothermia or having a side of beef fall on you…BUT the point is that dehydration is a serious problem. And if you happen to be in a place without water, you’ve get very few choices for how to replenish your precious bodily fluids.
You can catch bugs and suck the juices out of them, I suppose. You can use a divining rod to find hidden underwater aquifers. Or, and here comes the gross part, can you drink your own urine? To do so and to stay healthy requires you to have one amazing filtration system. Are those on the market good enough? Well, the good folks at Outside Magazine in this old post address that very issue: are today’s portable filtration systems good enough to allow you to drink you own pee?
That is about as interesting a question as there is, and the answer may surprise you.